Effect of Quinoa Protein Concentrate in Particulate and Fibrillar Forms on the Physico-Chemical Properties of Quinoa Starch Gels

Abstract The current study investigates the interactions between quinoa protein—both in particulate (protein concentrate, QPC) and fibrillar (QPF) forms—and quinoa starch (QS) gels, and how these interactions influence the thermal, pasting, and rheological properties of the gels. Gels were made by adding three different concentrations of QPC or QPF to a 10% QS dispersion (10, 25, and 50% w/w of starch). DSC results suggested an enhancement of amylopectin thermal stability and an acceleration of retrogradation upon a cooling stage by the addition of quinoa protein. FTIR spectra indicated that QS and QPC/QPF mostly interacted through hydrogen bonds. According to rheological measurements, in contrast to the increased G′ due to the addition of QPC (50%), only a slight increase in G′ was observed due to the addition of QPF (50%). Notably, this study is the first to directly compare the effects of QPC and QPF on starch gel properties, revealing that QPC markedly enhances gel elasticity. These findings highlight the potential application of the optimized quinoa starch-protein-based gels as functional ingredients in plant-based meat analogues, where improved textural and nutritional attributes are critical.